An experimental study of the transition in the wear regime of brake friction materials

Abstract

Brake friction materials (BFMs) are designed to have low wear rate under different conditions of contact pressure, temperature, and sliding velocity. The conditions to ensure a low wear rate (i.e., a moderate wear regime) between the disc and the BFM are not well established. The present article aims to enhance the comprehension about the wear regimes for BFMs. For this purpose, a commercial BFM was slid against a gray cast iron rotor (disc). Tests were performed under different sliding velocities and with both increasing and decreasing steps of pressure levels. Tribofilm formed on the disc's surface and BFM's wear were monitored during the tests. It was possible to conclude that the previous condition of the surface of the disc, with respect to the presence or absence of tribofilm, affects the required conditions for the transition in the wear regime. The removal of tribofilm on the surface of the disc was affected by high contact pressures and high sliding velocities. Those conditions led to a severe wear regime with a destruction of contact plateaus and an increase in friction and BFM's wear.

Thermal analysis and tribo‐performance evaluation of multilayered graphene and graphite based fly ash filled banana fiber reinforced brake friction composites

“…During sliding, the organic constituents (resin, fiber) and lubricants play essential roles in establishing the contact film/ plateaus at the interface, and this transfer layer become significant and more effective at higher load-speed conditions. [49][50][51] The hard ingredients within the composites act as a nucleus for forming rough or primary contact patches/plateaus. On the other hand, the degradation of organic ingredients results in smooth or secondary contact patches/plateaus formation.…”

Brazilian Tribology: origin, status quo and future perspectives

“…Then, the dynamics of the tribofilm formation and destruction on the rotor (brake disc) were studied. Finally, the relationship between the disc's tribofilm, contact plateaus, and operational parameters (contact pressure, sliding velocity and temperature) is investigated to understand their effects on wear regime transitions [394,395].…”

The Improvement of the Tribological Behaviour of Chemically Treated Abaca Fibre-Reinforced Polymer Composites

“…These accumulated wear particles were compacted on the surface of the primary plateaus, forming secondary plateaus [41]. Many relevant studies [42][43][44][45] showed that the presence of strong and compact secondary plateaus is very beneficial for the enhancement of the wear resistance of composites. In this work, relatively large secondary plateaus covered most of the area of the worn surfaces of samples PC3 and PC5, which is the primary reason for their lower wear rate and sum wear rate in Figure 7.…”